U.S. patent application number 10/592936 was filed with the patent office on 2007-10-18 for fuel cell system.
This patent application is currently assigned to Toyota Jidosha Kabushiki Kaisha. Invention is credited to Koji Katano.
Application Number | 20070243438 10/592936 |
Document ID | / |
Family ID | 34967109 |
Filed Date | 2007-10-18 |
United States Patent
Application |
20070243438 |
Kind Code |
A1 |
Katano; Koji |
October 18, 2007 |
Fuel Cell System
Abstract
A fuel cell system including a fuel cell body; a first portion
continuously supplied with heat following start up of the fuel cell
body; a second portion continuously supplied with heat following
start up of the fuel cell body; and a hydrogen exhaust valve. The
first portion and the second portion are directly fixed to each
other with the hydrogen exhaust valve disposed therebetween. The
first portion is, for example, a gas-liquid separation unit
supplied with heat from exhaust gas from the fuel cell body, and
the second portion is, for example, a hydrogen processing unit
supplied with heat from exhaust gas from the fuel cell body.
Inventors: |
Katano; Koji; (Susono-shi,
JP) |
Correspondence
Address: |
OLIFF & BERRIDGE, PLC
P.O. BOX 19928
ALEXANDRIA
VA
22320
US
|
Assignee: |
Toyota Jidosha Kabushiki
Kaisha
Toyota-shi
JP
471-8871
|
Family ID: |
34967109 |
Appl. No.: |
10/592936 |
Filed: |
April 25, 2005 |
PCT Filed: |
April 25, 2005 |
PCT NO: |
PCT/IB05/01101 |
371 Date: |
September 15, 2006 |
Current U.S.
Class: |
429/440 ;
429/469 |
Current CPC
Class: |
H01M 8/04089 20130101;
H01M 2250/20 20130101; H01M 8/04007 20130101; H01M 8/0662 20130101;
Y02T 90/40 20130101; Y02E 60/50 20130101; H01M 8/04268 20130101;
H01M 8/04164 20130101; H01M 8/04097 20130101; H01M 8/04253
20130101 |
Class at
Publication: |
429/026 ;
429/019 |
International
Class: |
H01M 8/04 20060101
H01M008/04 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 26, 2004 |
JP |
2004130024 |
Claims
1. A fuel cell system comprising: a fuel cell body; a first portion
and a second portion which form a passage for hydrogen exhausted
from the fuel cell body; and a hydrogen exhaust valve disposed in
the passage between the first portion and the second portion,
wherein the first portion and the second portion are directly fixed
to each other and are both continuously supplied with heat from the
fuel cell body following start up of the fuel cell body.
2. A fuel cell system according to claim 1, wherein the first
portion is a gas-liquid separation unit supplied with heat from
inflowing exhaust gas from the fuel cell body.
3. A fuel cell system according to claim 1, wherein the first
portion is an end plate provided in a stack configured by the fuel
cell body and supplied with heat liberated by the stack.
4. A fuel cell system according to claim 1, wherein the second
portion is a hydrogen processing unit supplied with heat from
inflowing exhaust gas from the fuel cell body.
5. A fuel cell system according to claim 4, wherein the hydrogen
processing unit is a dilution unit.
6. A fuel cell system according to claim 4, wherein the hydrogen
processing unit is a combustion unit.
7. A fuel cell system according to claim 1, wherein one of the
first portion and the second portion includes a cover formed with
an internal space that accommodates the hydrogen exhaust valve; and
the other one of the first portion and the second portion closes
the internal space of the cover within which the hydrogen exhaust
valve is disposed.
8. A fuel cell system according to claim 1, wherein a spring member
is interposed between the hydrogen exhaust valve and one of the
first portion and the second portion to urge the hydrogen exhaust
valve against the other one of the first portion and the second
portion.
9. A fuel cell system according to claim 1, wherein the hydrogen
exhaust valve is fixed to the first portion and the second
portion.
10. A fuel cell system according to claim 1, wherein seal
mechanisms are respectively interposed between the hydrogen exhaust
valve and each of the first portion and the second portion.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The invention relates to a fuel cell system provided with a
hydrogen exhaust valve.
[0003] 2. Description of the Related Art
[0004] In the fuel cell system field, fuel cells including an
exhaust valve are known such as that disclosed in Japanese Patent
Laid-Open Publication No. 2002-313389. This related technology
focuses on the need to thaw a frozen hydrogen exhaust valve when
the fuel cell is started up, and includes a warm-up box in which
the hydrogen exhaust valve is disposed and into which high
temperature air is fed.
[0005] However, with this related art, it is necessary to provide
passages and perform control in order to feed the high temperature
air into the warm-up box during the warm-up operation.
SUMMARY OF THE INVENTION
[0006] The invention has been conceived of in light of the
aforementioned problems, and provides a technology with a simple
structure that allows a frozen exhaust valve to be thawed when
starting up a fuel cell (and which prevents freezing of the exhaust
valve if it is about to freeze).
[0007] In an embodiment, which is one example of the invention, a
fuel cell system is provided with a fuel cell body; a first portion
continuously supplied with heat following start up of the fuel cell
body; a second portion continuously supplied with heat following
start up of the fuel cell body; and a hydrogen exhaust valve. In
this fuel cell system, the first portion and the second portion are
directly fixed to each other with the hydrogen exhaust valve
disposed therebetween.
[0008] According to the above described fuel cell system, a
configuration is provided in which the hydrogen exhaust valve is
interposed between the first and second portions that are
constantly supplied with heat following start up of the fuel cell.
Accordingly, it is possible to thaw the exhaust valve following
start up of the fuel cell (and, to prevent freezing of the exhaust
valve if it is about to freeze).
[0009] Further, it is preferable that the first portion of the
above fuel cell system is, for example, a gas-liquid separation
unit supplied with heat from exhaust gas from the fuel cell body.
However, this is merely one possible example of the first portion.
Accordingly, the invention is no way limited to this embodiment,
and, for example, the first portion may be an end plate provided in
a stack configured as part of the fuel cell body, or another
element.
[0010] Moreover, in the above fuel cell system, for example, the
first portion may include a cover formed with an internal space
that accommodates the hydrogen exhaust valve. Further, it is
preferable that the first portion and the second portion are
directly fixed to each other such that the second portion closes
the internal space of the cover within which the hydrogen exhaust
valve is disposed.
[0011] If this configuration is adopted, the internal space in
which the hydrogen exhaust valve is disposed functions like a heat
retaining chamber, which is extremely favorable for thawing the
exhaust valve when starting up the fuel cell (and, for preventing
freezing of the exhaust valve if it is about to freeze).
[0012] Further, it is preferable if the second portion in above the
fuel cell system is, for example, a hydrogen processing unit
supplied with heat from exhaust gas from the fuel cell body. In
this case, the hydrogen processing unit may be, for example, a
dilution unit or a combustion unit. Note that, this is just one
example of the second portion.
[0013] It is favorable if a spring member is interposed between one
of the hydrogen exhaust valve and the first portion, and the
hydrogen exhaust valve and the second portion.
[0014] According to the fuel cell system with this configuration,
the hydrogen exhaust valve is pushed against one of the first
portion and the second portion by elastic force of the spring
member. As a result, the hydrogen exhaust valve reliably abuts with
the first portion or the second portion.
[0015] In addition, the hydrogen exhaust valve disposed between the
first and second portions may be fixed to the first and second
portions.
[0016] Further, it is preferable that seal mechanisms are
respectively interposed between the hydrogen exhaust valve and the
first portion, and between the hydrogen exhaust valve and the
second portion.
[0017] In the above described configuration, the seal mechanism
interposed between the hydrogen exhaust valve and the first portion
and between the hydrogen exhaust valve and the second portion may
be, for example, an O-ring. In this case, it is possible to inhibit
leakage to the outside of the exhaust gas from the first portion,
and also to inhibit leakage to the outside of the flow of gas from
the hydrogen exhaust valve to the second portion.
[0018] The embodiment of the invention described above provides a
simple structure that allows a frozen exhaust valve to be thawed
when starting up a fuel cell (and which prevents freezing of the
exhaust valve if it is about to freeze).
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] The above mentioned and other features, advantages,
technical and industrial significance of this invention will be
better understood by reading the following detailed description of
the exemplary embodiment of the invention, when considered in
connection with the accompanying drawings, in which:
[0020] FIG. 1 is a schematic view that illustrates a fuel cell
system of an embodiment of the invention;
[0021] FIG. 2 illustrates an example of the fuel cell system of the
embodiment of the invention in which an exhaust valve is disposed
between a gas-liquid separation unit and a hydrogen processing
unit;
[0022] FIG. 3 is a schematic view that illustrates a first modified
example of the fuel cell system of the embodiment of the
invention;
[0023] FIG. 4 is a schematic view that illustrates a second
modified example of the fuel cell system of the embodiment of the
invention;
[0024] FIG. 5 illustrates an example of the second modified example
of the fuel cell system of the embodiment of the invention in which
the exhaust valve is disposed between the gas-liquid separation
unit and the hydrogen processing unit;
[0025] FIG. 6 shows the gas-liquid separation unit and the hydrogen
processing unit of FIG. 5 when viewed from the center right side of
FIG. 5;
[0026] FIG. 7 illustrates the attachment method used to attach the
exhaust value in a third modified example of the fuel cell system
of the embodiment of the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0027] In the following description and the accompanying drawings,
the present invention will be described in more detail in terms of
an exemplary embodiment.
[0028] As is apparent from FIGS. 1 and 2, a fuel cell system 20 of
the embodiment includes a circulation device 1; a gas-liquid
separation unit 2 (which corresponds to a first portion of the
invention); exhaust valves 3 and 4 (which correspond to a hydrogen
exhaust valve of the invention) that are controlled to open and
close by a control device (not shown), like an ECU; connecting
passages 5 and 6; a hydrogen processing unit 7 (that corresponds to
a second portion of the invention); seals 8 to 11 and 15; spring
members 12 and 13; and a fixed portion 14.
[0029] The circulation device 1 circulates fluid from a hydrogen
electrode side of a stack S of the fuel cell body. Hydrogen
supplied from a hydrogen tank (not shown) and hydrogen from the
gas-liquid separation unit 2 obtained by separation is mixed, and
then supplied to the stack S disposed downstream from the
circulation device 1.
[0030] The gas-liquid separation unit 2 separates inflowing exhaust
gas from the hydrogen electrode side of the stack S into gas and
liquids. The gas-liquid separation unit 2 has a hydrogen outlet
port 2a from which separated out hydrogen (note that, water,
impurities, and the like, are mixed in with this hydrogen) is
exhausted.
[0031] The hydrogen processing unit 7 processes the exhausted
hydrogen, and is, for example, a dilution unit or a combustion
unit. In this embodiment, an example using a dilution unit will be
described. The dilution unit 7 has a cover 7a and a gas passage 7b.
The exhaust valves 3 and 4, and the connection passages 5 and 6 are
housed within an internal space formed beneath the cover 7a; and
the gas passage 7b is formed integrally with the cover 7a. The
dilution unit 7 is directly fixed by screw fitting to the
gas-liquid separation unit 2 by inserting a bolt B into the fixed
portion 14 such that the gas-liquid separation unit 2 closes the
internal space beneath the cover 7a (refer to FIG. 2).
[0032] Next, the inter-connections of the elements within the
internal space of the cover 7a will be described. As can be seen
from FIG. 2, the exhaust valves 3 and 4 and the connection passages
5 and 6 are disposed within the internal space of the cover 7a.
These elements form a passage for hydrogen which is separated out
by the gas-liquid separation unit 2 and which flows in via the
hydrogen outlet port 2a. The separated out hydrogen passes along
this passage and eventually flows out from the cover 7a via a
hydrogen outlet port 7d provide at a inner side of the cover
7a.
[0033] The exhaust valve 3 is fixedly disposed between the
gas-liquid separation unit 2 and the cover 7a by inserting (or
fitting) a gas inlet port 3a and an outlet port 3d of the exhaust
valve 3 into, respectively, the hydrogen outlet port (exhaust valve
attachment port) 2a of the gas-liquid separation unit 2 and an
inlet port (exhaust valve attachment port) 7c of the connection
passage 5 at the inner side of the cover 7a. It should be noted
that the hydrogen outlet port (exhaust valve attachment port) 2a of
the gas-liquid separation unit 2 is coaxial with the inlet port
(exhaust valve attachment port) 7c.
[0034] A groove 3b is formed in the surface of the gas inlet port
3a of the exhaust valve 3 and extends in a circumferential
direction thereof. An O-ring 8 made of an elastic material like
rubber is fitted in the groove 3b and protrudes slightly therefrom.
The O-ring 8 acts as a seal. Accordingly, the exhaust valve 3 is
configured such that the gas inlet port 3a is inserted into the
hydrogen outlet port (exhaust valve attachment port) 2a of the
gas-liquid separation unit 2, whereby the O-ring 8 functions as a
contacting seal with the inner wall of the hydrogen outlet port
(exhaust valve attachment port) 2a.
[0035] Similarly, a groove 3e is formed in the surface of the
outlet port 3d of the exhaust valve 3 and extends in a
circumferential direction thereof. An O-ring 9 made of an elastic
material like rubber is fitted in the groove 3e and protrudes
slightly therefrom. The O-ring 9 functions as a seal. Accordingly,
the exhaust valve 3 is configured such that the outlet port 3d is
inserted into the inlet port (exhaust valve attachment port) 7c of
the connection passage 5, whereby the O-ring 9 functions as a
contacting seal with the inner wall of the inlet port (exhaust
valve attachment port) 7c of the connection passage 5.
[0036] Moreover, by fitting the exhaust valve 3 using the O-rings 8
and 9 made of elastic material in the above described manner, it is
possible to allow tolerance to absorb various kinds of assembly
errors.
[0037] Moreover, a spring member 12 (like a coil spring) is
disposed in an elastically deformed state between the inlet port
(exhaust valve attachment port) 7c of the connection passage 5 and
an exhaust valve body 3f. Accordingly, the spring member 12 exerts
a return force towards its original shape, and urges the exhaust
valve 3 in the direction toward the left side of FIG. 2. However, a
stepped portion 3c is formed in the gas inlet port 3a of the
exhaust valve 3, and this stepped portion 3c abuts with the
hydrogen outlet port (exhaust valve attachment port) 2a of the
gas-liquid separation unit 2. As a result, the exhaust valve 3 is
fixedly disposed between the gas-liquid separation unit 2 and the
cover 7a.
[0038] The exhaust valve 4 is fixedly disposed between the
gas-liquid separation unit 2 and the cover 7a by inserting (or
fitting) a gas inlet port 4a and an outlet port 4d into,
respectively, an outlet port (exhaust valve attachment port) 2b of
the connection passage 6 and the hydrogen outlet port (exhaust
valve attachment port) 7d of the inner side of the cover 7a. It
should be noted that the outlet port (exhaust valve attachment
port) 2b of the connection passage 6 is coaxial with the hydrogen
outlet port (exhaust valve attachment port) 7d of the inner side of
the cover 7a.
[0039] A groove 4b is formed in the surface of the gas inlet port
4a of the exhaust valve 4 and extends in a circumferential
direction thereof. An O-ring 10, which is made of an elastic
material like rubber, is fitted in the groove 4b so as to protrude
slightly from the surface. The O-ring 10 acts as a seal.
Accordingly, the exhaust valve 4 is configured such that the gas
inlet port 4a is inserted in the outlet port (exhaust valve
attachment port) 2b of the connection passage 6, whereby the O-ring
10 functions as a contacting seal with the inner wall of the outlet
port (exhaust valve attachment port) 2b of the connection passage
6.
[0040] Similarly, a groove 4e is formed in the surface of the
outlet port 4d of the exhaust valve 4 and extends in a
circumferential direction thereof. An O-ring 11 made of an elastic
material like rubber is fitted in the groove 4e and protrudes
slightly therefrom. The O-ring 11 functions as a seal. Accordingly,
the exhaust valve 4 is configured such that the outlet port 4d is
inserted into the hydrogen outlet port (exhaust valve attachment
port) 7d of the inner side of the cover 7a, whereby the O-ring 11
functions as a contacting seal with the inner wall of the hydrogen
outlet port (exhaust valve attachment port) 7d.
[0041] Moreover, by fitting the exhaust valve 4 using the O-rings
10 and 11 made of elastic material in the above described manner,
it is possible to allow tolerance to absorb various kinds of
assembly deviations.
[0042] Moreover, a spring member 13 (like a coil spring) is
disposed in an elastically deformed state between the hydrogen
outlet port (exhaust valve attachment port) 7d and an exhaust valve
body 4f. Accordingly, the spring member 13 exerts a return force
towards its original shape, and urges the exhaust valve 4 in the
direction toward the left side of FIG. 2. However, a stepped
portion 4c is formed in the inlet port 4a of the exhaust valve 4,
and this stepped portion 4c abuts with the outlet port (exhaust
valve attachment port) 2b of the connection passage 6. As a result,
the exhaust valve 4 is fixedly disposed between the gas-liquid
separation unit 2 and the cover 7a.
[0043] The exhaust valves 3 and 4 are connected via: the outlet
port 3d of the exhaust valve 3; the connection passage 5 extending
along the inner side of the cover 7a; the connection passage 6 that
extends in the axial direction of the exhaust valves 3 and 4 as far
as gas-liquid separation unit 2, and then extends along the side of
the gas-liquid separation unit 2; and then the inlet port 4a of the
exhaust valve 4.
[0044] Accordingly, the passage for the hydrogen which is separated
out by the gas-liquid separation unit 2 and which flows in via the
hydrogen outlet port 2a is formed in the internal space of the
cover 7a. The separated out hydrogen passes along this passage and
eventually flows out from the cover 7a via the hydrogen outlet port
7d provided at the inner side of the cover 7a.
[0045] Note that, the connection passage 6 and the connection
passage 5 are respectively formed at the gas-liquid separation unit
2 and the dilution unit 7 sides, and, as described previously, the
gas-liquid separation unit 2 and the dilution unit 7 are directly
fixed to each other by screw fitting. Accordingly, the connection
passages 5 and 6 are inter-connected and form the passage for the
separated out hydrogen. An O-ring 15 is provided in order to ensure
sealing between the two connection passages 5 and 6.
[0046] Next, the gas passage 7b will be described. The gas passage
7b is provided with an inlet port 7e, an inlet port 7f, a passage
7g, and an outlet port 7h. The inlet port 7e receives separated out
hydrogen, and the inlet port 7f receives exhaust gas from an air
electrode side of the stack S. Further, the hydrogen, etc., that
inflows from the inlet ports 7f and 7e is mixed in the passage 7g.
This mixed hydrogen, etc., then flows out through the outlet port
7h. As a result of this configuration, the hydrogen which includes
mixed-in impurities, etc., is discharged to the outside environment
after its concentration has been diluted by mixing with air.
[0047] In the fuel cell system of this embodiment, after start up
of the fuel cell, the gas-liquid separation unit 2 is continuously
supplied with heat (so long as the fuel cell is operating) by
inflowing exhaust gas from the hydrogen electrode of the stack S
that has been heated by an amount corresponding to the heat
liberated by the stack S. Similarly, after start up the fuel cell,
the dilution unit 7 is continuously supplied with heat (so long as
the fuel cell is operating) from the exhaust gases from the air
electrode side and the hydrogen electrode side of the stack S that
have been heated by an amount corresponding to the heat liberated
by the stack S.
[0048] With the above described configuration, the exhaust valves 3
and 4 are disposed within a space surrounded by the gas-liquid
separation unit 2 and the dilution unit 7 that are supplied with
heat from the exhaust gases from the stack (fuel cell main body) S
after start up of the fuel cell. Accordingly, when the fuel cell is
started up in low temperature environments, even if there is frozen
water within the exhaust valves 3 and 4, it is possible for it to
be thawed. Thus, there is no need to provide any special passages
or perform control for thawing. Moreover, in the case that the
water within the exhaust valves 3 and 4 is on the point of
freezing, it is possible to stop freezing from taking place.
[0049] Further, with the fuel cell system of the embodiment, the
number of fixed points is relatively small, and thus assembly time
can be reduced. Similarly, for the same reason, the volume required
for fixing is reduced, whereby the fuel cell system can be made
smaller. Moreover, since the number of members like pipes and
flanges (which have a larger surface area) that promote heat
radiation is reduced, it is possible to inhibit freezing from
taking place in low temperature environments.
[0050] In the above explanation of the fuel cell system of this
embodiment, the exhaust valves 3 and 4 are disposed in the internal
space surrounded by the gas-liquid separation unit 2 and the
dilution unit 7. However, the invention is not limited to this
configuration. For example, FIG. 3 shows a schematic view of a
first modified example, in which the gas-liquid separation unit 2
and the hydrogen processing unit 7 (for example, the dilution
unit), are directly fixed to each other, and the exhaust valves 3
and 4 are disposed to be adjacent with the gas-liquid separation
unit 2 and the hydrogen processing unit 7, respectively. If this
configuration is adopted, it is possible to realize the same
effects as when the exhaust valves 3 and 4 are disposed in the area
surrounded by the gas-liquid separation unit 2 and the dilution
unit 7.
[0051] Moreover, in the above explanation of the fuel cell system
of this embodiment, two exhaust valves, namely, the exhaust valves
3 and 4, are disposed in the space surrounded by the gas-liquid
separation unit 2 and the dilution unit 7. However, the invention
is no way limited to this configuration. For example, just one
exhaust valve, or more than two exhaust valves, may be provided.
For example, FIGS. 4 to 6 show a second modified example including
one exhaust valve. Note that, structural members of the
configuration shown in FIGS. 4 to 6 that are the same as those of
the previously described embodiment are denoted with the same
reference numerals, and an explanation thereof is omitted.
[0052] Further, in the above explanation of the fuel cell system of
this embodiment, the exhaust valves 3 and 4 are fixed by the spring
members 12 and 13. However, the invention is not limited to this
configuration. For example, in a third modified example shown in
FIG. 7, the spring member is disused on one side of the exhaust
valve 3, and a sealing method is adopted that utilizes surface
sealing and flange fixing (the same explanation applies to the
exhaust valve 4).
[0053] Moreover, in the above explanation of the fuel cell system
of this embodiment, the hydrogen processing unit (dilution unit) 7
and the gas-liquid separation unit 2 are directly fixed to each
other, with the internal space of the cover 7a being closed by the
gas-liquid separation unit 2. However, the invention is not limited
to this configuration. For example, in place of the gas-liquid
separation unit 2, an end plate with is part of the stack S may be
used to close the internal space of the cover 7a, and the hydrogen
processing unit (dilution unit) 7 may be directly fixed to this end
plate. This configuration is particularly favorable in the case of
fuel cell systems that do not require a gas-liquid separation
unit.
[0054] Moreover, although in the above explanation of the fuel cell
system of this embodiment the hydrogen processing unit 7 is a
dilution unit, the invention is not limited to this configuration.
For example, the hydrogen processing unit 7 may be a combustion
unit or another type of hydrogen processing device.
[0055] The invention may be embodied in a variety of other forms
that incorporate the essential features thereof, without departing
from the essence of the invention. Accordingly, the above described
embodiments are purely illustrative, and should not be taken to
restrict the scope of the invention in any manner whatsoever.
[0056] According to the invention it is possible to utilize a
relatively simple configuration in order to thaw a frozen exhaust
valve when starting up a fuel cell (and, to prevent freezing of the
exhaust valve if it is about to freeze).
[0057] The invention provides a fuel cell system including a fuel
cell body; a first portion continuously supplied with heat
following start up of the fuel cell body; a second portion
continuously supplied with heat following start up of the fuel cell
body; and a hydrogen exhaust valve. The first portion and the
second portion are directly fixed to each other with the hydrogen
exhaust valve disposed therebetween. The first portion is, for
example, a gas-liquid separation unit supplied with heat from
exhaust gas from the fuel cell body, and the second portion is, for
example, a hydrogen processing unit supplied with heat from exhaust
gas from the fuel cell body.
* * * * *